From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Cost of leaf road springs and the reasons for their expense.
| Identifier | ExFiles\Box 95\2\ scan0064 | |
| Date | 9th April 1936 | |
| To E.{Mr Elliott - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}8/KW.9.4.36. Cost of Leaf Road Springs. On Tuesday last the writer visited Firth's to urge the manufacture of a set of the new Ph.III rear springs F.88751 (Lec.5070) so that these can be tested in France on 32-EX with a rubber shackle at the front end only. While at Firth's we went into the question of the cost of our springs. The cost of the present Ph.III rear spring with no provision for a rubber shackle is £7. 18. 3d. The addition of a solid forged large eye at the front will considerably increase this cost. The reasons why our ordinary springs are so expensive, namely about 10 times what any other manufacturer pays are - (1) Firth's do not make springs for anyone else. (2) .060" is ground off both sides of every plate. (3) The plates are cadmium coated. (4) Grooves and holes for lubrication are provided. (5) Solid eyes cost more than rolled eyes. The material itself is a very small percentage of the cost. The introduction of a solid forged eye of outside dia. 2.450" necessitates starting with a plate possibly 3/4" thick. After bumping up the eye the plate is ground down to the finished size of about .300", a very costly operation. The oiling scheme shown on LeC.5070 means that the spring has to be completely assembled to mark off the hole in the top plate, and then taken to pieces to drill the hole. | ||